Tuning coil



July 25, 1933. G PORTS ET AL 1,919,905

TUNING COIL Filed Feb. 27, 1931 3 Sheets-Sheet l INVENTOR EARL G. PORTS BY HERMAN P. MILLER JR.

TUNING COIL Filed Feb. 27.- 1931 3 Sheets-Sheet 2 INVENTOR EARL c. PORTS BY HEAN P. MILLER JR.

ATTORNE Jgly 25, '1933. E, G. PORTS ET AL TUNING COIL Filed Feb. 27. 1.931 s Sheets-Sheet INVENTOR EARL G. PORTS BYHERMAN P. MILLER JR.

A TTOFx FIG. 6

FIG. 7

Patented July 25, 1933 UNITED STATES PATENT GFFIQE EAR-L G. PORTS, OF WOODSIDE, NEW YORK, AND HERMAN 1?.

llIELLER, JEh, OF EAST ORANGE, NEW JERSEY, ASSIGNORS T0 INTERNATIONAL CQDITMZU'ITICATTONS LABO- RATORIES, INC., OF NEW YORK, N. Y., A COIZPOEATIGN OF NEW YORK TUNING COIL Application filed February 2'7, 1931.

a mounting upon which the turns of a coil can be disposed and which is inexpensive,

simple, easily constructed, strong, durable and capable of permitting the coil thereon to be readily connected in operative relation.

The mounting proper comprises two end pieces to which are attached bars for supporting the coil or coils. The bars are attached to the end pieces in such a manner as to form a rigid cage-like structure.

The main portion. of the coil which contains the greater number of turns is arranged to encircle the mounting so suitable taps or leads can be readily attached thereto.

Another portion of the coil is arranged within the mounting in order that the turns bottom of the construction in Figure 1.

Figure 3 is an end View of another type of 0011 according to our invention.

Figure 4 1s a. bottom View of what appears in Figure 3.

Figure 5 shows a detail of certain parts shown to right of Figures 3 and 4.

Figure 6 is an end view of another form of our invention, and

Figure 7 is a plan or a side view seen from beneath the coil shown in Figure 6.

The same numerals identify the same parts throughout.

Referring first to Figures 1 and 2, we show a supporting framework having substantial- Serial Ne. 518,750.

ly the sh pe of acylindrical cage and comprising longitudinal bars 1 attached at their extremities to ends 2. The bars 1 and ends 2 are of insulation, the ends 2- have preferably the form of cylindrical discs and the bars 1 being engaged by the turns of the Coil indicated at 3. The movable contact arrangement provides for fine adjustment of inductance value when the main ,portion of inductance or coil 3 selected, by placing clips at desired. positions on the coil Each of the bars 1 consists of a deeper portion 5 somewha longer than onc-half the len th of the ba- 1 and another portion 5a of less transverse deptln and is of least depth at its cl remities which are affixed to the ends 2. file edges of these bars are notched to receive the turns 3 the larger part of the turns 3 being wound around the outside of the be 1 and a selected number of turns being disposed inside of the bars 1 entering notches on the inner edges of these bars so that they can co-operate with the contact 1.

The extremities of the bars fit into rece; 7 in the circumferential edges of the ends 2 and are. secured in any suitable manner as by means of pins 8 driven to suitable holes made by boring the extremities of bars 1 and ends 2 shown in Figures 3, 4, 6 and 7. The extremities of the coil are s cured to the ends 2 by means of bolts 9.

To secure a sup-porting framework of this construction in position, we provide a bracket 10 with openings for screws 11 which.

serve as terminal leads. The bracket 10 has the two arms 70 attached to the main portion by the angle piece 12 by means of the screws 71 The two arms 70 are attached to the ends by the screws 72.

The ends 2 have openings to provide bearings f r the shaft 13 wnich rotates the contact or conductor arm 1'. This shaft has a metallic section 1 1 one extremity and a similar metallic section 15 at the other extremity these two sections being supported in the ends 2 and connected by an intermediate section 16 of insulation. Couplings 17 and 1S connect the sections 16 to the sections 14 and 15. The coupling 18 is preferably metallic and on the other extremity of the portion 15 is a metal collar 19 which cm rotate when the shaft rotates in contact with a conducting brush 20 secured by a block 21 to the adjacent end 2.

At 22 is a yoke, the arms of which are pivotally connected to the sleeve 18 by pin 23. This yoke is of metal and contact between it and the coupling 18 is secured by a short length of flexible conductor 24. To

the outer end. of the yoke are attached blad 25 and 26 of conducting material. The blade .25 is fairly stiff while 26 flexible. One of these blades rests upon one face of the turns 3 of the coil and the other presses against the other face of the same turn. The turns are in the form of flat bands which project inside beyond the edges of bars 5a. The contact arm 4 can thus not is turning, but it can also swing on its pivot 23 and thus move over the entire length of the limited number of turns 3 as are attached to the inner edges of the bars 1. One terminal of the circuit is connected to the lnush 20 and the other to the screw 9 at the opposite end of the coil. The number of turns can, of course, be varied by the addition or subtraction of all the turns 3 engaging in i the inner edges of the. bars 501 or less than all according to the number desired. Any suitable means for turning the shaft 13 can of course be employed.

We mount upon the shaft 13 outside of "the framework a pinion 27 which meshes with the gear 28 mounted on a bracket 29 by means of screw which passes through ends 2 and is held by a nut as shown.

Notchcs 31 are provided as a means of ad justing the angle of rotation of the gear. Adjustment is accomplished by filing the notches t0 the depth required. Otherwise, bracket 29 would have to be cut to a precise width. The gear 28 rotates only far enough to carry the stop 30 from one of the notches 31 in bracket 29 into the other. Since the gear 28 is larger than the gear 27, the contact arm 4 can therefore make several rev olutions, but with the diameters of the gears 27' and 28 properly chosen the arm is limited in its movement so that it can only travel from one end to the other over the turns 3 which'are on the inside of the supporting framework of the coils.

This kind of framework can be made strong and durable and answers very well for the purpose of supporting a coil for radio work, such as the loading coil of an antenna. By rotating the arm 13 the numthe turns 3 of a coil wound around the outside of the bars 1.

These bars have the same shape as before except that they are of uniform depth between the ends 2 and ti eir extremities are reduced to engage the recesses 7 of these ends. Two of these bars, however, are of greater thickness and are disposed in opposite ends of a diameter as at la. in Figures 3 and 4 to provide bearings for a hoilow cylinder 33 of insulating material which is mounted on the inside of the framework to carry a coil in adjustable ind e. si .e relation to the coil, comprising the turns 3, which is fixed. By shifting the position of the tubular member 33, the coupling between the inside and outside coils can, of course, be varied.

To mount the tubular member 33, we use journals 34 rotatably supported. in the bars la. and rigidly attached to opposite sides of the tubular member These ournals or trunnions 34 are of metal and turn in sleeves of insulating material. inserted through bores in bars la and held by pins 36 which prevent th a h .ves 35 from turning. The sleeves project beyond the outside faces of the bars la and extend into bores provided in blocks of insulation 37. These blocks have apertures to align with similar apparatus in the bars la to receive fibre bolts 38 carrying nuts 39 which prevent displacement of the blocks 37. The block 37 at the left in Figures 3 and 5 has a shoulder made by attaching piece of metal 40, and the as- "ed trunnion 34 projects through the :l-z 37 and carries on its outer end a head which enables it to be secured by a screw the like to a flexible conductor 42. Screws secure the metal block 40 and block 37 together. On the opposite side of the tubular member the trunnion 34 carries on its outer extremity a. head 44, allixed by a screw or any other suitable means. This head is encircled by a flange 45 and it earries in its extremity a notch or kerf 46 to fit the end of a screw-(.lriver or other tool so that the position of the tubular member 33 can be varied. e also attach to the adjacent face of the block 37 a block 47 of suitable material, preferably metal, this block having a slot therein as shown at 48 to receive the edge of the flange 45, screws 49 securing the block 47 to the block 37; block 47 having bores for these screws of larger diameter from one face inasfar as the slot 48 is placed so that the heads of the screws 49 may be well within the block 47. Another screw 51 passes in. through block 47, engaging a threaded portion of the block 47 at its inner end, and so allows clamping of flange 45 to retain rotatable elements in any desired position. A conductor 52 is secured by a screw 53 to the block 47 and, connected with the adjacent trunnion 34 by inserting its opposite extremity into a notch in the head 44 as shown at 54 in Figure 5. The

collar or flange 45 may have projecting studs 55 to prevent rotation of the rotatable portion more than a desired amount by striking against block 47 at either extremity of rotation. This conductor-is flexible and permits rotation of the adjacent trunnion 34: when member 33 is to be turned. The turns of the coil on this member are shown at 56 and this coil is connected at its opposite ex tremities to the trunnions 34 which are affixed to the member 33 in any feasible manner. This construction serves very well in coupling an antenna to the co-operating circuits of a sending or receiving device, the coil on the member 33 preferably being di rectly in the antenna circuit. Obviously, this device can be used for other circuits also.

In Figures 6 and 7 the supporting framework consists of bars 1 all of the same shape attached to ends 2; with a coil comprising turns 3 wound around the outside of the framework; and with another coil inside the framework; the coil inside being preferably fixed and the two coils co-axial. The inside coil is wound upon a tubular member 57, one end of which has a cross-bar 58 and the other a cross-bar 59. These two cross-bars can be of pieces of insulation of the same material as themember 57 fitted inside the ends of the member 57 and secured bypins 8. The ends 2 may be bridged by cross-bars 60 and 61 secured by screws 62. The bar 58 may be affixed to the bar 60 and the bar 59 to the bar 61. The bars 60 and 61 may be employed to attach the entire construction to any suitable device such as the inside of a casing or cabinet wherein the coil is to be supported for use. At 9 the extremities of the outside coil are connected to the operating circuit and the terminals of the inside coil are shown at 63 and 64. These terminals have the form of bolts which constitute convenient binding posts for the circuit conductors.

This construction also provides a strong durable yet easily built framework and the 1. A supporting framework for an eleo-.

trical coil comprising ends connected by longitudinal bars, a spiral conductor having its turns fitting into notches in said. bars, some of said turns encircling the bars and the re maining turns being surrounded thereby and disposed in notches on the inner edges of said bars, a central shaft supported in bearings in said ends, a conductor arm pivotally connected to said shaft in contact with said last named turns, means for limiting the rotary movement of said shaft, wherein the shaft comprises metallic extremities connected by an insulating section, the conductor arm comprising blades which engage different portions of the conductor, and the means for limiting the rotary movement of the shaft comprises gears one of which has a projection, and a bracket attached to the framework to serve as a stop for said projection.

2. A supporting framework for an electrical coil comprising ends connected by longitudinal bars, a spiral conductor having its turns fitting into notches in said bars, some of said turns encircling the bars and the remaining turns being surrounded thereby and disposed in notches 011 the inner edges of said bars, a central shaft supported in bearings in said ends, a conductor arm pivotally connected to said shaft in contact with said last named turns, means for limiting the rotary movement of said shaft, and means for mounting the framework including a bracket attached to said ends and having fastening members which also serve as terminal leads for the coils.

EARL G. PORTS. HERMAN P. MILLER, J R. 

